I have the following array of objects that comes from a MySql query:

[
  {col1:1, col2:a},
  {col1:1, col2:b},
  {col1:1, col2:c},
  {col1:2, col2:d},
  {col1:2, col2:e},
  {col1:2, col2:f},
  {col1:3, col2:g},
  {col1:3, col2:h}
]

I would like to transform into the following object:

[
  {col1:1, col2:[a,b,c]},
  {col1:2, col2:[d,e,f]},
  {col1:3, col2:[e,g,h]}
]

Is there a way to perform this task using map or array filter?